1. Field of the Invention
The present invention pertains to methods and compositions for lubricating rubber surfaces especially those rubber surfaces that are proximate to needleless medical injection sites and valves.
2. Background
In many medical applications, it is necessary to provide a coupling site which includes a rubber valve surface or septum that is to be penetratingly engaged by a sharp hypodermic needle or the like so that fluids such as blood, nutrients or medications can be admitted to a patient's circulatory system through a fluid flow line.
Due to the sharp nature of a needle tip and the ever present fear that infectious disease may be spread via transmission through a needle-pierced or pricked skin area, medical coupling sites and associated fluid feed mechanisms have now been provided that include a coupling site having a rubber valve area surrounding a slit through which a blunt male luer or cannula is inserted. In many designs, after insertion, the luer or cannula is rotated so as to lockingly engage a threaded locking collar or the like. After insertion through the valve slit, the desired fluid is admitted to the fluid flow line that is attached to the coupling site that, in turn, communicates with the circulatory or other body system of the patient.
Usually, the penetrating cannula or male luer is composed of a rigid plastic material, typically polycarbonate. As the cannula is inserted through and rotated in the valve slit, considerable frictional resistance is encountered, especially in those cases where the rubber in the valve surface has been cured via peroxide curing processes. Synthetic rubber, such as peroxide cured polyisoprene has a high frictional coefficient and an effective lubricant is therefore needed at this valve site area since it is highly desirable from an economic perspective to leave the valve and its associated coupling site attached to the patient for multiple fluid admission applications.
Accordingly, an effective method and composition are needed to provide continued lubricity to the valve surface even after numerous cannula penetrations and withdrawals through the valve slit. This requirement dictates that an effective lubricant must remain in place proximate the valve slit over prolonged periods of time.
Additionally, since it is the common practice to sterilize the coupling site and its associated valve surface after each withdrawal and prior to the next cannula penetration with isopropanol, (IPA) the lubricant should be relatively inert to and not miscible with the IPA. Additionally, in many cases, the coupling site will be subjected to irradiation sterilization, so an effective lubricant should also be capable of undergoing such sterilizing methods without significant deterioration.